Test And Analysis On Seismic Performance Of Frame Structure Of Steel Reinforced Concrete Beam And Steel-tube Encased Concrete Column

With the sustained and rapid development of social economy in our country, the improving of the level of science, the continuous development of structure science and construction technology and the require of building functions of the people, high-rise buildings, super high-rise buildings and long span structures have got broad application and development.Then, steel-concrete composite structures get the rapid development and wide application.Based on the advantages of big span, high load carrying capacity and the small size of cross-section for steel-concrete composite beam, in order to improve the seismic performance of frame structure and simplify the construction,a new type of frame structure system, steel reinforced concrete beam and steel-tube encased concrete column, is presented. This paper conducts a test on two frame structures of steel reinforced concrete beam and steel-tube encased concrete column under horizontal low cyclic loading. The test process and failure mode are observed, and the hysteretic behavior, skeleton curves, stiffness degradation, energy dissipation, and residential deformation of the two frames is studied. Meanwhile, the law of strain values of longitudinal bars, flanges and steel-tube in the beam and column end are analyzed carefully, and the order of plastic hinges is given. The test results show that hysteretic curves of the two specimens are plump, and one also behaves good energy dissipation when it is prestressed, and they behave good seismic performance. Meanwhile, the hoop strains of steel-tube of plastic hinge in the column bottom changes unevenly during the whole loading, and they could supply effective constraint on compressive concrete. And the cracks could be delayed when the steel reinforced concrete beam is prestressed. Furthermore, the sequence of plastic hinges of the two specimens is ’beam ends before and column bottoms after’, so that the mechanism of energy dissipation for beam plastic hinges and a delayed occurring of plastic hinges for column bottom could be achieved. Then, imitate the mechanics performance of the frame structure of steel reinforced concrete beam and steel-tube encased concrete column with finite element software based on the theory of three dimensional unit and fiber beam-column unit.The result shows the calculation agrees well with the results of field test and finite element method. At last, parameters are studied based on the numerical model and the restoring force model of the frame structure of steel reinforced concrete beam and steel-tube encased concrete column has been put forward, and the numerical model can forecast the hysteretic behaviors of this frame well.